Georgia-Pacific Gypsum unveils DensDeck Prime Roof Board with EONIC Technology, which offers enhanced water resistance and increased vertical pull strength. According to the manufacturer, DensDeck Prime Roof Boards with EONIC Technology have manufacturing specifications that include a surface water absorption rate of 1 gram, and a total water absorption rate of 5 percent.

According to the company, in independent testing of total water absorption, alternative coated glass mat gypsum roof boards absorbed 76 percent more water more water than 1⁄2-inch DensDeck Prime Roof Boards with EONIC Technology, while 1⁄2-inch gypsum fiber boards absorbed 132 percent more. In independent testing of surface water absorption, 1⁄2-inch gypsum fiber absorbed 2.3 times more water than the new formulation, while alternative coated glass mat gypsum roof boards absorbed 4 times more water.

Finally, in vertical pull strength tests, DensDeck Prime Roof Boards with EONIC Technology were found to be 74 percent stronger than 1⁄2-inch gypsum fiber boards on the face, and 14 percent stronger on the back, notes the manufacturer. When compared to alternative coated glass mat gypsum boards, DensDeck Prime Roof Board is 2.5 times greater strength on the face, and 7 times more strength on the back.

The American Hydrotech Extensive Garden Roof Assembly was installed on two sections of the roof. The system was topped with pre-grown mats featuring mature sedum plants. Photo: American Hydrotech Inc.

The Chicago Blackhawks have captured the hearts of the city of Chicago along with three Stanley Cups in the last decade. The Blackhawks routinely lead the league in attendance at the United Center, and fans were excited when the team announced it would build a new 125,000-square-foot training facility and community center in downtown Chicago.

Completed earlier this year, the MB Arena features two NHL-sized ice rinks and other amenities including a fitness center, dining options, and spaces that can be rented for outings and events. The facility is the practice site for the Blackhawks and also hosts youth hockey, adult hockey leagues and public skating.

When plans for the project were unveiled, architects and planners mandated the facility meet or exceed all green and sustainable standards for the city. Chicago has been a leader in promoting vegetative roofs to help control storm water runoff, and this new construction project was no exception. The arena includes the construction of 24,000 square feet of green roof systems to complement the structure’s 68,000-square-foot main roof. A 60-mil TPO system manufactured by Carlilse SynTec was specified for the upper roof assembly, and plans called for an American Hydrotech Extensive Garden Roof Assembly to be placed on two lower sections of the roof.

The Garden Roof Assembly

Architect HOK worked with American Hydrotech during the design stage to select roofing components and plants that were optimized for the climate conditions and the building’s structural limitations.

According to Dennis Yanez, national marketing manager, American Hydrotech, and Kevin Serena, garden roofing technical sales coordinator for the central region, the structure’s metal deck necessitated a lightweight system.

“Our 4-inch extensive garden roof system was ideal for this project,” says Yanez. “Since part of this project had a metal deck, there are more structural capacity concerns than with a concrete deck, so we were able to put together a lightweight, built-in-place system.”

The assembly consists of a hot-applied rubberized asphalt membrane, MM6125, which is applied to the roofing substrate to form a monolithic coating. It is topped with a root barrier and Dow Styrofoam insulation. The system also incorporates Hydrotech’s Gardendrain GR15, a molded polyethylene panel designed to retain water, filter fabric, lightweight growing media, and mature plants.

The plants are installed in the form of the InstaGreen Sedum Carpet, a pre-grown mat that comes in 25-square-foot rolls. It contains between nine and 15 different types of sedum and provides instant coverage when it is installed.

Key benefits of the system include reducing the urban heat island effect, purifying the air, and limiting storm water runoff, notes Yanez. “The Extensive Garden Roof Assembly is able to capture more than 1.5 inches of water on the roof, which plays a major role in storm water management,” he says.

The system also protects the membrane from ultraviolet (UV) degradation and damage from wind-blown debris. “Most importantly, for us, a garden roof is just another version of a PMR, or protected membrane roofing,” says Yanez. “Because the membrane is always in a PMR application, with Dow insulation over it, whatever ballast — whether it’s gravel ballast, or architectural pavers, or the garden roof assembly — is in place makes it literally impossible for the membrane to get damaged. It also mitigates the climate swings, keeping the membrane at a more constant temperature year-round.”

This system has a proven track record, according to Yanez. “We’ve been doing this going back 50 years on parking decks under regular topsoil, where weight wasn’t a concern,” he points out. “This is just a more modern version of that, but we’re putting it on the 4th, or the 14th, or the 99th floor.”

The Roofing Installation

All American Exterior Solutions, Lake Zurich, Illinois, is an approved applicator for both key manufacturers. The union contractor installed the Carlisle TPO system on the building’s main roof and the Hydrotech green roofs on the two lower roof levels.

Willie Hedrick, division manager at All American Exterior Solutions, notes that the TPO roof was installed first. “The deck was acoustic, so first we had to lay strips insulation in the flutes over the entire main roof,” he says.

The lightweight growth media was lifted to the roof in 2-yard totes. Photo: Christy Webber Landscapes.

Areas that housed mechanical equipment were reinforced with two layers of 5/8-inch DensDeck from Georgia-Pacific. Two layers of 2.6-inch insulation were then installed, followed by the 60-mil TPO, which was mechanically attached using the RhinoBond system from OMG Roofing Products. The attachment system uses induction welding technology to attach the membrane to the fasteners and plates that secure the insulation — without penetrating the membrane.

The main roof was originally designed as fully adhered system, but work began in January, and the temperature constraints ruled out some adhesives. “Once we made the switch to RhinoBond, we were able to install the membrane even though we did it during the winter,” Hedrick says.

Most of the TPO roof was surrounded by high parapet walls, and in other areas the safety perimeters were marked with flags. “At a few points at the highest points of the main roof we had to put up some the flags, and if you were outside of the flags you had to be tied off,” notes Hedrick. “The mid-roofs had short parapet walls, and on those roofs, we set up flags and had 100 percent fall protection outside the safety perimeter. For the lower green roof, we put guardrails up on the parapet to eliminate the fall hazard.”

The Garden Roofs

After the TPO sections were installed, work began on the extensive garden roof assemblies. The mid-roof had a metal deck, so the first step was to screw down 5/8-inch USG Securock cover board and strip in the seams. “At that point, we installed the liquid-applied membrane and the protection board,” Hedrick says.

The second green roof was installed over a concrete deck, so the application was a bit different. The membrane was applied directly to the concrete. A late change was made in the configuration of the lower green roof to take advantage of the space. “The owner decided to add a terrace to the lower green roof so people could walk out and see the roof and views of the city,” Hedrick recalls.

Before the growing media and plants were added, electronic field vector mapping (EFVM) was conducted by International Leak Detection to determine if there were any voids in the membrane. “You’ve got to confirm everything is 100 percent watertight before we start setting the components down,” Hedrick says. “We usually do the test and start putting the components down the next day to minimize exposure. The subcontractor we worked with to do the landscaping, Christy Webber, performed well. Since some of the components are loose laid, we worked with them to put down enough soil to hold everything in place. We worked hand-in-hand getting the all of the components and soil in.”

The Landscape Work

Jim Waldschmidt, project manager for Christy Webber Landscapes, Chicago, oversaw the installation of the lightweight growing media and sedum mats on the roof. Christy Webber is a full-service union landscaping company, and Waldschmidt notes that roofing work is a small but growing share of the company’s business. “We work with a few different commercial roofers,” he says. “This year we’ve done maybe 10 commercial projects.”

After the growing media was evenly spread out, the sedum mats were laid into place by crews from Christy Webber Landscapes. Photo: Christy Webber Landscapes.

Logistics at the site made for an easy delivery and setup — an unusual situation in downtown Chicago. “We were able to deliver the soil almost a week before we were scheduled to go out there, so we had everything on site and knew we wouldn’t have to worry about waiting,” Waldschmidt notes. “We just had to bring in a crane and lift up the soil bags. We had a pretty easy installation compared to other green roofs we’ve done.”

Growing media was lifted to the roof in 2-yard tote bags, which were cut open to disperse the contents. Three days after the growing media was in place, Christy Webber crews returned to install the sedum mats. “The sedum mats are delivered on pallets almost like the way a roll of sod would be delivered,” says Waldschmidt. “We just had to set the pallets on the roof, pull off the sedum mats and unroll them.”

A temporary irrigation system was set up to help the plants get established in the hot July temperatures. “Everything looks great now,” Waldschmidt says. “All of the sedum up there is thriving.”

Growth Sector

In this high-profile project, with a high-profile owner, making sure the system was error-free was critical, notes Serena. “Chicago is definitely the leader in vegetative roofs, and has been for more than 10 years,” he says. “This is another prime example. There was never a question whether this building would have a green roof on it. It’s a credit to Chicago, and it is a credit to the Chicago Blackhawks.”

Hedrick is proud to be part of the green roof movement. “I like the challenge, and I like the diversity,” he says. “When the Blackhawks went to the Stanley Cup championship and the blimp was hovering over the arena, I could see a couple of my projects on TV. It reminded me of all the time, effort, attention to detail, and collaborative hard work that it took to produce the final product. We’re turning typically unusable roof areas into useful space for amenities.”

The key driver of green roofs is storm water management, notes Yanez, but turning rooftops into useful space is another key benefit. “We’re seeing more and more city incentives for storm water management,” he says. “In urban areas, people are also taking advantage of existing space with green roofs. It’s a growing industry — pun intended.”

U.S. Bank Stadium is topped with a PVC roof system that display’s the company’s logo. Photo: Johns Manville

When discussions began about the new U.S. Bank Stadium in Minneapolis, Minnesota, there was a request for an outdoor stadium. However, state and local government provided funding specifically for an indoor stadium that would be able to host major events like the professional football championship game and the college basketball championship game. As a result, a translucent roof and mobile front windows were designed to allow natural light to enter the stadium and to give fans a view of downtown Minneapolis. The mobile windows also allow fans to experience outdoor elements while providing protection from snow, rain and cold winter weather. The roof design was developed taking into consideration the budget and the region’s weather; it would be costly to make it retractable, and a sloped roof lends to a more secure option for snowy weather.

Challenging Task

Berwald Roofing Company Inc., headquartered in North St. Paul, Minnesota, installed an adhered PVC roof system manufactured by Johns Manville over the structure’s metal deck. In all, 280,000 square feet of grey 60-mil PVC were installed. The system also included a vapor barrier and two layers of 1.6-inch ENRGY 3, a rigid roof insulation board composed of a closed-cell polyisocyanurate foam core with fiberglass reinforced facers. Half-inch DensDeck Prime cover board from Georgia-Pacific was also installed.

The roofing portion of the project began in April 2015, with an aggressive completion deadline of November 1, 2015. The schedule and logistics on the project posed major hurdles. “Getting material 300 feet up to the roof was our biggest challenge,” says Berwald Roofing Senior Project Manager Steven Hegge. “A big part of that was scheduling time to share the cranes with the iron workers and general contractor.”

Another challenge was storing material during the installation due to the limited amount of space on the roof. “All the decking had to be installed as we went along, just before roof installation,” Hegge states. “We were on a very tight time schedule in this multiple-phase construction project.”

“The general contractor and Berwald Roofing have worked with Johns Manville on numerous stadium projects in the past and preferred to use JM PVC on this complicated stadium project,” notes Johns Manville sales rep Bob Deans. “This application is on a 3.75-inch to 12-inch slope on the north side of the building, which adds to the difficulty of installing a fully adhered PVC roof assembly.”

The Solution

Due to restricted loading space at the jobsite, materials arrived to Berwald’s yard directly from the manufacturer. They were then loaded on Berwald Roofing semi-trucks each day for delivery. Once they arrived at the site, they were immediately lifted to the roof via tower cranes and installed in the most efficient time frame, to meet the owners expected installation timeline.

The stadium seats approximately 65,000 people for most games. However, this space is built to be expandable to hold up to 73,000 attendees for special events such as the professional football championship game, which the stadium is scheduled to host on February 4, 2018, and for events like the college basketball championship game, which will be held there in 2019. U.S. Bank’s logo is prominently displayed on the rooftop. Charcoal grey 60-mil PVC membrane was cut to specification using a computerized cutter to create an exact replica of the U.S. Bank logo. Berwald Roofing then adhered the charcoal grey PVC on top of the grey 60 mil PVC membrane using JM PVC low-VOC membrane adhesive and then heat-welded the edges of material to finish the application of the logo.

Work on the first phase of the Orlando International Airport expansion project includes the South Airport Intermodal Terminal Facility and APM Complex, which features a standing seam metal roof

Architectural Sheet Metal Inc. has been in servicing the Orlando area for more than 23 years, specializing in commercial metal roofs and wall systems, primarily new construction. When Matthew Leonard, the company’s vice president, found out that the Orlando International Airport was proposing a new terminal project with a metal roof, he jumped at the chance to submit a bid.

He wanted to land the job because it would be the largest project the company has ever tackled, and one of its most prominent. He also wanted it for another reason—he knew he’d see it every time he drove to the airport. “For many years now, we’ve specialized in standing seam metal roofs. It’s our bread and butter,” he says. “We’ve done lots of schools, government building, military bases. It’s just something we enjoy doing. When this project came around, right here in our backyard, we knew we wanted to take it on. It’s larger than anything we’ve ever done, but it’s our specialty.”

The South Airport Intermodal Terminal Facility and APM Complex is a new construction project that coordinates mass transit for the airport, including regional rail systems and the Automated People Mover (APM). It’s part of the first phase of an ambitious $2 billion plan to almost double the size of the airport.

Architectural Sheet Metal installed the Berridge standing seam metal roof system, as well as internal aluminum gutters and a custom-fabricated aluminum bullnose that runs along the perimeter of the roof

The building encompasses approximately 200,000 square feet, and the structure is primarily covered with a standing seam metal roof. The scope of work for Architectural Sheet Metal included installing the metal roof system and internal aluminum gutters. It also included custom fabrication and installation of an aluminum bullnose that runs along the perimeter of the roof. “Every roof is radiused, and some sections have compound double raiduses,” Leonard notes. “The trickiest part of the project is probably the bullnose because all of the gable ends of the roof are radiused, and the large bullnose has to be welded on in 30-foot sections.”

Another tricky thing about the project is that the work was divided into two different contracts with two different construction managers. On one side of the building, which houses the monorail and parking garage, the project is overseen by Hensel Phelps, and on the other side, which handles the train lines, the construction is overseen by a Turner-Kiewit joint venture. The dividing point is a building expansion joint that runs across the middle of the roof. “We’re one of very few subcontractors out here that has a contract with both of the construction managers,” Leonard says. “They both have their own agendas, their own timelines, and their own completion dates, and it was a delicate balancing act working with the two of them.”

Installing the Roof

The roof system was designed to unify the elements of the structure and tie the building together. Some sections of the roof cover the building, while others serve as canopies, so there are two types of metal deck on the building. “The area we call the spine has a 3-inch-thick acoustical deck,” Leonard explains. “That was interesting because before we could put our 6 inches of polyiso on, we had to install batten insulation in the flutes. The acoustical decking is perforated, so you can see through it. That’s a little different, when you’re so high up. It spooked the guys at first to be able to see right through it.”

Crews dried in the entire roof with a waterproofing underlayment from MFM Building Products specifically designed for high-temperature applications.

The other sections were comprised of standard type B metal deck. Sections covering the interior were insulated, while canopy sections were covered with 5/8-inch DensDeck from Georgia-Pacific.

After the underlayment was applied, the welded aluminum gutters were installed. “The longest piece was 78 feet,” says Leonard. “We fabricated the sections, water-tested them and shipped them out. We used a crane to lift them to the roof.”

The roof system was supplied by Berridge Manufacturing, and the 24-gauge galvalume metal panels were roll formed at the site. “Berridge has a ZEE-Lock double-lock standing seam panel,” Leonard says. “We own one of their portable roll formers, and we have it on site here. We pick it up with a crane, and lift it up to the edge of the roof, and we actually roll form our largest panels straight out to the roof. The guys just catch the panels as they come out of the roll former.”

Metal roof panels were roll formed at the site. For most roof sections, the roll former was hoisted by a crane, to the edge of the roof, and crew members stacked the panels as they come out of the roll former.

Panels were stacked in piles of 10 for installation. There were 12 different roof surfaces, so as the roll forming crew moved along, other crews would start installing the panels. “Every stack was tied down with strapping to ensure that it wasn’t susceptible to wind,” Leonard points out. “With a hurricane in the forecast, we were very careful about that.”

The panels in the spine area had a tighter radius, so those panels were formed on the ground using separate curving machine. Lining up the panels perfectly was critical. “With a radiused roof, it’s sometimes harder to find things to measure off to ensure your panels are straight. This panel is a left-to-right system. It’s a male-female overlay with a continuous clip that Berridge manufactures. The panels are hand-crimped together, and then you do the first and second stage of the double-lock panels with an electric seamer. You just turn it on and it goes up and over.”

Details, Details

Fall protection posts were installed during the framing process, which helped with safety planning but posed problems when it came to detailing. “It’s nice to have permanent fall protection points to tie into, as everyone had to be 100 percent tied off, but there are close to 200 fall protection posts on the project that we had to cut around and flash,” Leonard says. “I’ve never seen so many posts on a roof like that.”

The aluminum bullnose was constructed after precise measurements were taken at the site. After they were custom painted to match the roof, the 30-foot sections were lifted into place and installed.

Because the posts were tied into the structural steel and couldn’t be moved, the company designed and manufactured a welded aluminum flashing detail to ensure they all looked the same no matter where they landed in the panel profile. “We set up a welded aluminum flashing that should last forever, and it’s welded, so it shouldn’t leak. We try to go above and beyond in our flashing details.”

Leonard points to his company’s fabrication experience as a key to its strength. “We try to be more than just a roofing company,” he says. “We try to be a custom metal fabrication company that fabricates the panels to precise specifications determined by the site. We custom fabricate metal and then, as roofers, we install it. We like to have that double whammy. Not many people have that ability to do both.”

The company’s expertise came in handy on the bullnose. “The bullnose was originally bid as 22-gauge metal,” he says. “We looked at it and we didn’t like it. It’s a large, 9-inch radius, and we felt the thin, light-gauge metal would shake in the wind. Every 10 feet would be a lap joint with caulk, which would be susceptible to wind damage. We came up with the idea of using a welded piece of .080 aluminum. Once it was approved, we purchased a 100-ton press brake with a custom die to fabricate this bullnose.”

The bullnose was constructed from precise measurements taken at the site. “We took the radius off of the building and created jigs in our warehouse,” Leonard explains. “We welded pieces together in 30-foot sections, and we shipped them to a local painter who coated them with baked-on Kynar to match the roof.”

The bullnose was designed to hook into the gutter strap and wrap around onto the fascia, where it is screwed into the framing. In areas where there is no gutter, sections of the bullnose are equipped with a larger flange with an S-hook built into it to attach it to the roof. Corner pieces tie it all together.

Watching Out for Irma

Dealing with two different GCs was challenging, in part due to changes in the schedule. “Originally, we were supposed to finish one side first and then start the other side, but both phases of the project ended up starting around the same time,” says Leonard. “This doubled the manpower we needed on the job.”

Photos: Aerial Innovations

For changes like the bullnose, Architectural Sheet Metal had to make sure RFIs were submitted and approved by both sides. “Sometimes it was hard to keep track of who we submitted it to, but it worked to our benefit at times. Once it was approved by one side, it was easily approved by the other.”

The schedule had the crews working in hurricane season, and precautions were taken to make sure the job site was prepared for high winds. “When Hurricane Irma was approaching, I checked every single weather update every day until it made landfall,” Leonard recalls. “It hit on a Monday, and a full week ahead of that we were cleaning the roofs and preparing the gutters. We removed all debris on the jobsite because any trash on the roof could clog the downspouts. We added more and more men to the process throughout the week, and we shut the jobsite down on Wednesday. We took all of the material we had, stacked it, bundled it together, and we were able to move it all inside the building. We were pretty well complete on the Hensel-Phelps side, and Turner Kiewit brought in 40-foot Conex boxes for us to put our material in and secure it. They tried really hard to make sure the jobsite was secure.”

As the storm progressed, it deviated from the projected path, and no one could be certain which direction the winds might be coming from. “We just had to start battening everything down,” Leonard recalls.

Photos: Architectural Sheet Metal Inc.

Stacks of panels on the roof that were not yet installed were strapped every 2 feet on center. The entire state was in emergency mode, making things difficult. “For four or five days before the storm even hit, we couldn’t find water, rope and extension cords. Grocery stores were running out of supplies. Gas stations were running out of gas.”

After the storm passed, Leonard breathed a sigh of relief. The roof wasn’t damaged. The panels that had already been installed were in great shape, and the uninstalled panels weren’t harmed.

Elements like the weather are beyond anyone’s control, and Leonard notes his company tries to control as many variables as it can. “We have full control over the actual fabrication of the material and the quality of it,” he says. “When I call something in, I talk to our guy who works with me. Our company oversees it. Every morning I stop by the shop and follow up on the process on the way to the job site. We install it. I can make sure everything is OK.”

The project is nearing completion, and Leonard can’t wait to finish a landmark project he’ll see every time he makes a trip to the airport. “You can’t miss it,” he says. “It’s huge.”

The map showcases the growing number of job sites adopting DensElement Barrier System as their preferred sheathing solution across the United States. Using the project map, online visitors can explore projects by location, or project type (e.g., sports/recreation, education, healthcare, government/municipality, etc.).

This new tool creates a visual way for architects, engineers, contractors and building owners to gain perspective on the accelerating adoption of DensElement Barrier System on high-profile projects across the country. “DensElement is an innovative, proven solution progressive architects and contractors can rely on, and we want to share the successes that these customers are experiencing,” said Jason Peace, Senior Director of Marketing and Product Management for Georgia-Pacific Gypsum.

The DensElement Barrier System, with AquaKOR Technology, integrates the water-resistive and air barrier (WRB-AB) directly into its gypsum core, beneath the fiberglass mat to create a consistent, performance-tested WRB-AB. According to the manufacturer, the product eliminates the need for building wrap, fluid-applied membranes or peel-and-stick membranes. It’s faster to install and can be installed when it’s wet outside, saving time and labor. The all-in-one Dens brand system is finished with PROSOCO R-Guard FastFlash liquid flashing to fill and seal joints, fasteners, openings, penetrations and transitions. DensElement Barrier System is ABAA listed and WRB-AB approved, and has a customized MasterSpec® specification – 061656 Air and Water Resistive Sheathing Board.

The millions of passengers who pass through Denver International Airport each year no doubt have the usual list of things to review as they prepare for a flight: Checked baggage or carry-on? Buy some extra reading material or hope that the Wi-Fi on the plane is working? Grab
a quick bite before takeoff or take your chances with airline snacks?

The storm created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the original membrane.

Nick Lovato, a Denver-based roofing consultant, most likely runs through a similar checklist before each flight. But there’s one other important thing he does every time he walks through DIA. As he crosses the passenger bridge that connects the Jeppeson Terminal to Gate A, he always looks out at the terminal’s roof and notices with some pride that it is holding up well. Fifteen years ago, after a hailstorm shredded the original roof on Denver’s terminal building, his firm, CyberCon, Centennial, Colo., was brought in as part of the design team to assess the damage, assist in developing the specifications and oversee the installation of a new roof that would stand up to Denver’s sometimes unforgiving climate.

HAIL ALLEY

DIA, which opened in 1995, is located 23 miles northeast of the metropolitan Denver area, on the high mountain desert prairie of Colorado. Its location showcases its spectacular design incorporating peaked tent-like elements on its roof, meant to evoke the nearby Rocky Mountains or Native American dwellings or both. Unfortunately, this location also places the airport smack in the middle of what is known as “Hail Alley”, the area east of the Rockies centered in Colorado, Nebraska and Wyoming. According to the Silver Spring, Md.- based National Weather Service, this area experiences an average of nine “hail days” a year. The reason this area gets so much hail is that the freezing point—the area of the atmosphere at 32 F or less—in the high plains is much closer to the ground. In other words, the hail doesn’t have time to thaw and melt before it hits the ground.

Not only are hail storms in this area relatively frequent, they also produce the largest hail in North America. The Rocky Mountain Insurance Information Association, Greenwood Village, Colo., says the area experiences three to four hailstorms a year categorized as “catastrophic”, causing at least $25 million in damage. Crops, commercial buildings, housing, automobiles and even livestock are at risk.

Statistically, more hail falls in June in Colorado than during any other month, and the storm that damaged DIA’s roof followed this pattern. In June 2001, the hailstorm swept over the airport. The storm was classified as “moderate” but still caused extensive damage to the flat roofs over Jeppesen Terminal and the passenger bridge. (It’s important to note that the storm did not damage the renowned tent roofs.) The airport’s original roof, non-reinforced PVC single-ply membrane, was “shredded” by the storm and needed extensive repair. Lovato and his team at CyberCon assessed the damage and recommended changes in the roofing materials that would stand up to Colorado’s climate. Lovato also oversaw the short-term emergency re- pairs to the roof and the installation of the new roof.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings.

Under any circumstances, this would have been a challenging task. The fact that the work was being done at one of the busiest airports in the world made the challenge even more complex. The airport was the site of round-the-clock operations with ongoing public activity, meaning that noise and odor issues needed to be addressed. Hundreds of airplanes would be landing and taking off while the work was ongoing. And three months after the storm damaged the roof in Denver, terrorists attacked the World Trade Center, making security concerns paramount.

INSPECTION AND REROOFING

Lovato’s inspection of the hail damage revealed the extent of the problems with the airport roof. The original PVC membrane, installed in 1991, was showing signs of degradation and premature plasticizer loss prior to being pummeled by the June 2001 storm. The storm itself created concentric cracks at the point of hail impacts and, in most cases, the cracks ran completely through the membrane. In some instances, new cracks developed in the membranes that were not initially visible following the storm. The visible cracks were repaired immediately with EPDM primer and EPDM flashing tape until more extensive repairs could begin. Lovato notes that while nature caused the damage to DIA, nature was on the roofing team’s side when the repairs were being made: The reroofing project was performed during a drought, the driest in 50 years, minimizing worries about leaks into the terminal below and giving the construction teams almost endless sunny days to finish their job.

The initial examination of the roof also revealed that the existing polystyrene rigid insulation, ranging in thickness from 4 to 14 inches, was salvageable, representing significant savings. Although a single-ply, ballasted roof was considered and would have been an excellent choice in other locations, it was ruled out at the airport given that the original structure was not designed for the additional weight and substantial remediation at the roof edge perimeter possibly would have been required.

Lovato chose 90-mil black EPDM membrane for the new roof. “It’s the perfect roof for that facility. We wanted a roof that’s going to perform. EPDM survives the best out here, given our hailstorms,” he says. A single layer of 5/8-inch glass-faced gypsum board with a primed surface was installed over the existing polystyrene rigid insulation (secured with mechanical fasteners and metal plates) to provide a dense, hail-resistant substrate for the new membrane.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof.

In some areas adjacent to the airport’s clerestory windows, the membrane received much more solar radiation than other areas of the roof. When ambient temperatures exceeded 100 F, some melting of the polystyrene rigid insulation occurred. “That section of the roof was getting double reflection,” Lovato points out. To reduce the impact of this reflection, the roof was covered with a high-albedo white coating, which prevented any further damage to the top layer of the polystyrene rigid insulation board and also met the aesthetic requirements of the building.

LONG-TERM SOLUTION

Lovato’s observations about the durability of EPDM are backed up by field experience and controlled scientific testing. In 2005, the EPDM Roofing Association, Washington, D.C., commissioned a study of the impact of hail on various roofing membranes. The study, conducted by Jim D. Koontz & Associates Inc., Hobbs, N.M., showed EPDM outperforms all other available membranes in terms of hail resistance. As would be expected, 90-mil membrane offers the highest resistance against punctures. But even thinner 45-mil membranes were affected only when impacted by a 3-inch diameter ice ball at 133.2 feet per second, more than 90 mph—extreme conditions that would rarely be experienced even in the harshest climates.

Lovato travels frequently, meaning he can informally inspect the DIA roof at regular intervals as he walks through the airport. He’s confident the EPDM roof is holding up well against the Denver weather extremes, and he’s optimistic about the future. With justified pride, Lovato says, “I would expect that roof to last 30-plus years.”

Georgia-Pacific Canada LP, an affiliate of Georgia-Pacific Gypsum, a manufacturer of gypsum products, has expanded its coast-to-coast sales presence in the country.

Three independent sales representative firms, all based in Canada, cover specific territories.
· Div7 Building Systems, based in Surrey, BC, will cover British Columbia
· North 49 Sales Agency Inc., based in Toronto will service Ontario, Quebec and Atlantic Canada.
· Pilot Group Inc., based in Calgary, AB, will operate in The Prairie Provinces.

According to Leo Bissonnette, regional business manager – Canada & Northeast US, Georgia-Pacific Gypsum, the companies represent all gypsum products, including innovative Dens Brand fiberglass mat panels. This team will focus on building owners, architects and roofing contractors, complementing the work of the company’s internal field sales managers, who focus on drywall contractors and distributors.

Div7 Building Systems is a manufacturers’ representative agency whose prime focus is the promotion of premium manufacturers outlined in Division 7 of the construction specification category. Its principals are Enzo Saponaro, P. Eng., who has more than 16 years of experience in the construction industry, and Robert Jahnsen, who has more than 19 years of sales experience in the construction industry.
Contact information:
Enzo Saponaro
Email: enzo@DIV7.ca
Phone: (604) 644-5934

North 49 Sales Agency Inc. is a building products sales agency owned and operated by Marc G. Allaire, who has been involved in the building science and roofing industries since 1980 in the areas of engineering, sales, marketing, building science and project management. Allaire and his team bring a wealth of experience in distribution to the table.
Contact information:
Marc G. Allaire
Email: Mallaire@north49sa.com
Phone: (416) 996-6164

Pilot Group Inc., under the direction of its president, Larry Shoesmith, has operated as a sales agency since 2002. Pilot Group represents manufacturers of quality products to cover a wide range of building envelope solutions for building owners, architects, consultants and contractors.
Contact information:
Larry Shoesmith, CTR
Email: larry@pilotgroup.ca
Phone: (403) 560-2107

Thanks to Georgia-Pacific LLC‘s acquisition of Temple-Inland Building Products, its Georgia-Pacific Gypsum division is bigger—but more importantly, better.

With integration of two of the industry’s most experienced building materials manufacturers now complete, a larger and even more experienced team of employees is offering customers a broader range of products, more convenient distribution and—soon—new systems designed to improve customer service.

Among the highlights of the “new” Georgia-Pacific Gypsum are:

More Products: The company’s enhanced portfolio of products offers customers more UL approved fire-rated assemblies; a growing family of lightweight products; the addition of paper-faced sheathing, shaftliner and soffit boards to the ToughRock family; and wider availability of the trusted Dens line of fiberglass mat gypsum panels.

More Convenient Distribution: With the addition of high-quality assets, we’ve added 40 percent more capacity and a wider geographic footprint, giving customers added peace of mind when placing an order for any of the numerous products in the Dens and ToughRock product families.

Improved Customer Service: By adding 350 talented employees, Georgia-Pacific Gypsum now has an experienced and trusted 2,000-person workforce determined to make doing business with the company easier than ever.

“Georgia-Pacific Gypsum is now bigger and better than ever, offering customers products, distribution and service unparalleled in the industry,” says Mike McCoy, vice president of marketing for Georgia-Pacific Gypsum. “We are delighted with the swift integration of Temple-Inland Building Products’ talented people, high-quality plants and products, allowing us to further optimize the customer experience.”

Georgia-Pacific completed its $710 million acquisition of Temple-Inland Building Products assets from International Paper Co. in July 2013. The purchase included facilities that manufacture the following building materials: fiberboard, gypsum products, lumber, medium density fiberboard (MDF) and particleboard.

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January/February 2018

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About Roofing

Roofing is a national publication that unravels, investigates and analyzes how to properly design, install and maintain a roof system. Through the voices of professionals in the field, Roofing’s editorial provides a unique perspective.